Latest Engine Mod Keeps JSTARS Viable, Says Northrop Grumman

The E-8C JSTARS test bed took off for the first time on December 14 with the standard of JT8D engines that will be fitted to the entire fleet if funding allows. (Photo: Northrop Grumman)

Northrop Grumman is hoping that funds to re-engine the first two operational E-8C JSTARS radar surveillance aircraft will be provided in the Fiscal 2013 budget next year. The test bed aircraft is now flying with JT8D-219 engines that Northrop Grumman has modified with a new pneumatic system that it claims “vastly improves reliability and the hardware’s life cycle.” Although the JT8D is hardly new technology, the 17 operational E-8Cs are powered by even older JT3Ds. A $1.7 billion program to replace them was started some years ago, and the test bed first flew with JT8Ds in December 2008. But funding to proceed with the upgrade was later restricted, while the U.S. Air Force launched a study of alternative means of providing ground moving target indicator (GMTI) radar maps to ground forces. Responding to the study, Boeing has suggested replacing the E-8C fleet with a version of the P-8 Poseidon, based on the 737-700.

But according to Dave Nagy, Northrop Grumman vice president of business development for Battle Management and Engagement Systems, only the 707-based JSTARS is large enough to meet the continuing requirement. The cabin volume, payload weight, available power and endurance of the E-8C are all superior, he told AIN. The JT8D retrofit was an easy solution for maintaining the aircraft’s cost-effectiveness, with only new pylons required. The new engines, with their single-stage precooler, would pay for themselves within eight years through reduced maintenance costs and better fuel efficiency. Nagy explained that retrofitting newer, higher-bypass CFM56 turbofans–as was done to a portion of the KC-135 fleet–was not an option. Their additional weight would require significant wing modifications, and their larger diameter affects the look angle of the APY-7 surveillance radar.

Nagy noted that the JSTARS capability had again been proved during the recent air operations over Libya, where the aircraft’s large onboard crew provided real-time targeting support that was especially valuable since there were no ground troops to designate targets. Looking ahead, Nagy said the new AN/ZPY-2 ground surveillance radar would be “significantly more agile and effective” if fitted to the E-8 as an APY-7 replacement. The new radar, also known by the acronym MP-RTIP, is being developed jointly by Northrop Grumman and Raytheon. It is currently scheduled to be fitted only to the Global Hawk UAV.